In this project we will use neuroanatomical, electrophysiological and pharmacological techniques to examine the sympathetic and parasympathetic reflex mechanisms involved in the neural control of urinary bladder and large intestine of the cat. The project will focus on two major areas: (1) the mechanisms underlying transmission in vesical and colonic parasympathetic ganglia and (2) the organization of the lumbar sympathetic outflow to the bladder and intestine, including afferent pathways, as well as the spinal interneuronal and preganglionic neuronal systems. Specific topics to be explored are: (1) the identification of peptide neurotransmitters in peripheral ganglia and visceral primary afferent systems, (2) the role of inhibitory and facilitatory mechanisms in modulating transmission in peripheral ganglia, (3) plasticity in ganglionic pathways following neural damage, (4) the morphology of autonomic ganglion cells and their synaptic inputs, (5) the central projections of visceral primary afferents at the thoracolumbar level, and (6) the identification in the lumbar spinal cord of interneuronal and preganglionic cell groups involved in excretory reflexes. The ultimate objectives in this investigation are to provide a wiring diagram for lumbar sympathetic pathways which control micturition and defecation, and to provide a more complete description of the central and peripheral ganglionic mechanisms that integrate the sympathetic and parasympathetic inputs to the excretory organs. It is anticipated that this research will provide further insight into the function of peptides in the nervous system, and the organization visceral afferent and spinal interneuronal mechanisms; two areas that have received relatively little attention. The study of lumbar sympathetic pathways has considerable clinical relevance since it is now recognized that abnormal sympathetic nervous activity may contribute to disorders of excretory function, particularly in the lower urinary tract. Thus, it seems reasonable to expect that the information to be gained in the proposed experiments about central reflex mechanisms and the identity of neurotransmitters in the lumbar sympathetic pathways will lead to more effective diagnoses and pharmacological treatment of urinary and intestinal dysfunction.